EWS module device for electro-winning and/or electro-refining, interconnection process, and operating process thereof

ABSTRACT

The invention relates to an EWS module device for electro-winning and/or electro-refining, based on a saturated leaching solution of PLS/electrolyte/raffmate/ILS without solvent extraction, characterised by comprising: a tank ( 10  and  12 ); a set of electrolytic cells contained within the tank, wherein the cells are electrically and volumetrically separated by the internal walls of the module ( 14 ), with the cells being connected in series by a joining board or capping board ( 3 ); an intercellular bar ( 1 ); an intercellular bar guide ( 2 ); inlet and outlet ducts for the PLS/electrolyte/raffinate/ILS ( 17 ) and ( 11 ) for each cell independently; and each EWS module is in turn connected to the other modules by an inter-module connector ( 18 ), and same in turn control the connection and disconnection of the EWS modules by an interrupter ( 25 ); operating process of the EWS module device; and connection and disconnection process between different EWS module devices.

TECHNICAL FIELD OF THE INVENTION

The technical field of this invention refers to mining, specifically tothe devices for hydrometallurgy, electrowinning and/or electrorefining.

BACKGROUND OF THE INVENTION

Obtaining copper cathodes on a large scale is a process known in thestate of the art. This process, to be profitable, is intensive for largevolumes of material to be obtained. The basis of this process is oneused for the first time in south Wales in 1869, where electrorefiningwas tested as a purification process for metallic copper that is carriedout in electrolytic cells and consists of the application of an electriccurrent to dissolve impure copper. In this way, the purest possibleelectrolytic copper is obtained, with 99.99% purity, which permits itsutilization as an electric conductor, among other applications. Chile isone of the principle producers and refiners of copper in the world.

The total process for electrowinning copper is known by the techniciansin this subject and operates as follows: it starts with the crushing ofthe material (CH), then comes the agglomeration process (AG), this isfollowed by the lixiviation process (LX), followed by the extraction bysolvents (SX), to end, finally, with the electrowinning (EW), to endwith the obtaining of a copper cathode.

The stages presented previously, in that order, reveal the knownprocess. Each one of the stages, individually, has its own technicalproblems, of which we wish to highlight those that are presented below.

The Electrowinning (EW) stage in itself, is a stage that requiresdevices with specific electrical and volumetric capacities in order toobtain copper cathodes, especially when the copper solution is notconcentrated in a previous stage of extraction by solvents.

On the other hand, the traditional electrowinning (EW) stage has alwaysbeen executed at a fixed location due to the large number of equipment,electrical support, intensive process and handling of high tonnages ofmaterial that this operation requires.

The electrolytic extraction processes (EW) are generally carried out inundivided electrochemical cells that contain an electrolytic bath (witha high concentration of copper previously extracted by solvents) and amultiplicity of anodes and cathodes. In such processes, such as forexample the electroplating of copper, the electrochemical reaction thattakes place in the cathode (manufactured in stainless steel), conductsthe deposition of copper in metallic form on the cathode itself. Theanode, generally manufactured of lead, is consumed slowly forming theanodic sludges and producing gaseous oxygen, as residual elements(WO2013/060786).

In general, what is known by the state of the art mentions that thistype of process uses continuous current in parallel through eachanode-cathode pair, as mentioned in patent WO 2013117805. In fact,rectifiers are used to compensate the system's direct current input withthe current the electrochemical process on its own requires.

Another of the common stages of the total process in electrowinning, butprior to subjecting the electrolyte to the current, is the oreenrichment or concentration stage by extraction of same with solvents, astage also called Pregnant Leach Solution (PLS). This stage is necessaryto reach a copper concentration in the electrolyte of about 7 to 48 g/Lof electrolyte. These concentrations are necessary to make theelectrowinning process economically viable in medium and large-scalemining.

SUMMARY OF THE INVENTION

In a first aspect of this invention, it is a EWS (Electrowinning Series)module-type device that permits the obtaining of cathodes ofelectrolytic copper using the pregnant leach solution (PLS) directly inthe electrowinning (Lixiviation with Electrowinning Direct-LED),avoiding the stage of ore concentration by extraction with solvents(FIG. 1, L1, L2, L3 and L4).

On the other hand, with this type of cell cathodes may also be obtainedfrom solutions of:

-   -   Electrolyte with a high concentration of copper (of 4 to 50 g/l)        in solution.    -   Electrolyte disposal solution (over 20 g/1 of copper)    -   Solution of raffinate with a low concentration of copper    -   Solution of ILS (Intermediate Leach Solution) with a low        concentration of copper.

A second aspect of this invention is that the EWS module devices aremounted in modular form, connected electrically from one EWS module toanother by means of the cathodes-anodes and continuous current switchesand the complete device can be mobilized physically depending on thedemand of the process itself.

A third aspect of this invention involves the type of current with whichthe EWS module device operates, with which the electrolyte dissolved inthe electrowinning is refined, in such a way that in this invention itbehaves like a circuit of continuous current in series and not inparallel as it is executed at present.

A fourth aspect of this invention is that the EWS module permits workingwith larger volumes of a strong solution from the lixiviation and withranges from the smaller concentrations of dissolved copper up to highconcentrations of copper (conventional electrolyte).

A fifth aspect of this invention is to achieve a high velocity of masstransference towards the cathode with a low specific area of the same(m²/kg of cathode), with low concentrations of copper and high incomingflows in the cell.

A seventh aspect is to use a low continuous current in the EWS moduledevice with a lower energy consumption (increasing current efficiency in99% in the EW process) because the traditional processes use a highcontinuous current, making its influence felt in a high-energyconsumption. The continuous current delivered by the rectifier isexactly the same as the one applied in the electrowinning process foreach cathode.

An eighth aspect is that the consumption of electric current becomesindependent of the number of cathodes and anodes.

A ninth aspect is that the EWS module has between 2 to 100 separations,preferably 10 separations that correspond to the electrowinning cells,where each cell has supports for the anodes and cathodes that permit theregulation of the separation between anode and cathode, an independentaeration system for each cell and its respective outlets for thesolution using the overflow method.

A tenth aspect is the process of connecting and disconnecting the EWSmodules from each other.

Finally, this EWS module device produces a big impact on small andmedium-sized mining because of the low investment and operation costthat these devices require and being able to outsource this part of theprocess that adapts to the production capacity they possess because itis modular and mobile.

The technical problems that the EWS module device hopes to resolve are:

-   -   obtain copper cathodes with electrolytic quality based on        different types of solutions:        -   a pregnant leach solution (PLS), without passing through the            step of concentration by extraction using solvents (SX)        -   an electrolyte with a high concentration of copper in            solution that originates from the extraction by solvents            (SX) stage        -   an ILS solution with a low concentration of copper        -   a raffinate solution with a low concentration of copper        -   A discard electrolyte with a high concentration of copper in            solution.    -   obtain that the continuous current of the electric power system        in the EWS module is exactly the same as the current that the        electrochemical process requires for electrowinning copper        cathodes, that is, the electrowinning process is a circuit of        continuous current in series.    -   Achieve electrowinning copper directly from an ore lixiviation        solution with a low concentration of copper, that contains        between 4 and 45 g/L of copper in solution.    -   make use of an electrowinning-intensive process where it is        required (physically), for the amounts that are required and in        the shortest possible time and likewise, the plant can be moved        when the work site no longer requires its services.    -   Obtain high velocity mass transference towards the cathode with        a low specific surface of the same (m²/kg of cathode), with low        concentrations of copper and high incoming flows in the EWS        module.    -   use of a low continuous current in the rectifier that feeds the        EWS module with a lower energy consumption (increasing current        efficiency in 99%) unlike the traditional processes where the        rectifiers operate at high currents, which results in a higher        energy consumption.    -   Making the consumption of electric current independent of the        number of cathodes and anodes.    -   Simple connection and disconnection between EWS modules.    -   Handling of volumes of electrolyte in parallel and not in series        as is done traditionally.

DESCRIPTION OF THE FIGURES

FIG. 1/13

The figure represents a general diagram of the productive process inwhich this invention is inserted.

The line of arrows of the upper part of the diagram shows the physicalphenomena that the water suffers in the different positions of themovement of the ore:

X: Impulse pumps

0: Flow controllers and temperature meters

F1: Evaporation of the mixed pool

F2: Evaporation of the ILS pool

F3: Evaporation piles

F4: Evaporation in EW

F5: Decomposition of water by electrolysis

F6: Washing water to discard

F7: Production of copper cathode

The line immediately below the arrows of the upper part shows thebehavior of the solid material in the different positions of themovement of the ore:

G1: Agglomerated ore from the crusher-binder

G2: Dynamic pile

G3: Gravel to dump

In the following line of arrows, the handling of the acid is presented:

H1: Sulfuric acid from trucks

H2: Acid TK

H3: Sulfuric acid to agglomeration.

In the following line of arrows, the handling of the process water ispresented:

I1: Process water from water supply

I2: Service water

I3: ILS pool

I4: Mixed pool

I5: Emergency pool

The last line presents the system's heating network:

J1: Oil supply

J2: Boiler

J3: Water conditioning chamber

J4: Heat exchangers

There are other parts associated to the adaptation and preparation ofthe LPS before the EWTECH-LED:

K1: Chemical product, concentrated Guar

K2: Chemical product, concentrated cobalt sulfate

K3: Guar TK, this is a tank where the Guar is diluted in water and isleft at an optimum concentration to be applied to the PLS that is sentto the cells of the modules of the EWTECH-LED plant.

K4: Cobalt TK, this is a tank where the cobalt sulfate is diluted inwater and is left at an optimum concentration to be applied to the PLSthat is sent to the cells of the EWS modules of the EWTECH-LED plant.

K5: TK Bank 2, this is a tank where the PLS/Electrolyte/Raffinate/ILS isreceived, in series, when it has passed once through the first bank ofthe EWTECH-LED system. (Without restricting the number of banks to beused except when the concentration of the PLS/Electrolyte/Raffinate/ILSreaches a range below 4 gr/L.)

K6: TK Bank 3, this is a tank where the PLS/Electrolyte/Raffinate/ILS isreceived in series when it has passed once through the second bank ofthe EWTECH-LED system. (Without restricting the number of banks to beused except when the concentration of PLS/Electrolyte/Raffinate/ILSreaches a range below 4 gr/L.)

K7: TK Bank 4, this is a tank where the PLS/Electrolyte/Raffinate/ILS isreceived, in series, when it has passed once through the third bank ofthe EWTECH-LED system. (Without restricting the number of banks to beused except when the concentration of copper in the PLS solution reachesa range below 4 gr/L.)

K8: TK transfer bank, this is a tank where the PLS is received, inseries, that has passed once through the fourth bank of the EWTECH-LEDsystem. (Without restricting the number of banks to be used except whenthe concentration of the PLS reaches a range below 4 gr/L.) The PLS usedis transferred to the mixed pool.

L1: EWTECH-LED bank N° 1 (this invention)

L2: EWTECH-LED bank N° 2 (this invention)

L3: EWTECH-LED bank N° 3 (this invention)

L4: EWTECH-LED bank N° 4 (this invention)

FIG. 2/13

This figure represents a flow diagram of the Electrowinning processdirect in series EWTECH-LED.

In the line of arrows of the lower right part of the diagram, thephysical phenomena that the water suffers in the different positions ofthe movement of the ore are presented:

F5: Decomposition of water by electrolysis

F6: Washing water to discard

F7: Production of copper cathodes

F8: Evaporation of water by atmosphere

F9: Cathode washing water

The following line of arrows presents the handling of the acid:

X: Impulse pumps

0: Flow controllers and temperature meters

H4: Sulfuric Acid to EW-LED.

The following line of arrows presents the handling of the process water:

16: Process water to EW-LED

17: LX emergency shower

18: Service water for human consumption

The last line presents the system's heating network:

J1: Oil supply

J2: Boiler

J3: Water conditioning chamber

J4: Heat exchangers

There are other parts associated to the adaptation and preparation ofthe PLS before the EWTECH-LED:

K1: Chemical product, concentrated Guar

K2: Chemical product, concentrated cobalt sulfate

K3: Guar TK, this is a tank where the Guar is diluted in water and isleft at an optimum concentration to be applied to the PLS that is sentto the cells.

K4: Cobalt TK, this is a tank where the cobalt sulfate is diluted inwater and is left at an optimum concentration to be applied to the PLSthat is sent to the cells.

K5: TK Bank 2, this is a tank where the PLS is received, in series, whenit has passed once through the first bank of the EWTECH-LED system.(Without restricting the number of banks to be used except when theconcentration of the PLS reaches a range below 4 gr/L.)

K6: TK Bank 3, this is a tank where the PLS is received, in series, whenit has passed once through the second bank of the EWTECH-LED system.(Without restricting the number of banks to be used except when theconcentration of the PLS reaches a range below 4 gr/L.)

K7: TK Bank 4, this is a tank where the electrolyte in series isreceived when it has passed once through the third bank of theEWTECH-LED system. (Without restricting the number of banks to be usedexcept when the concentration of copper in the PLS solution reaches arange below 4 gr/L.)

K8: TK transfer bank, this is a tank where the PLS is received, inseries, that has passed once through the fourth bank of the EWTECH-LEDsystem. (Without restricting the number of banks to be used except whenthe concentration of the PLS reaches a range below 4 gr/L.) The PLS usedis transferred to the mixed pool.

L1: EW TECH-LED bank N° 1

L2: EWTECH-LED bank N° 2

L3: EWTECH-LED bank N° 3

L4: EWTECH-LED bank N° 4

The following line of arrows presents the handling of the PLS and aline:

M3: PLS/PLS recirculated from LX

M4: PLS recirculated/raffinate to LX

The following numbering also shows:

21: PLS to conditioning

22: Sulfuric acid to line

23: Process water to line

24: PLS to E/E heat exchanger

25: PLS to E/A heat exchanger

26: Cobalt sulfate to Cobalt Sulfate TK

27: Guar to Guar TK

28: Cobalt sulfate solution

29: Guar solution to distribution

30: Guar solution to Bank EW 1

31: Guar solution to Bank EW 2

32: Guar solution to Bank EW 3

33: Guar solution to Bank EW 4

34: PLS to Bank EW 1

35: PLS to Bank EW 2

36: PLS to Bank EW 3

37: PLS to Bank EW 4

38: PLS to Transfer TK

39: PLS in recirculation to pool

40: Hot water from heater

41: Hot water to Cobalt Sulfate TK

42: Hot water to Guar TK

43: Hot water to heat exchanger

44: Hot water to cathode washing

45: Hot water in return

46. Process water to services and operation

47. Water to EW-LED emergency service

48. Service water to human consumption

49. Process water to replacement

50: Water to heater

51: Petroleum to heater

52: Evaporation of water in EW bay

53: Decomposition of water in EW bay

54. Cathodic copper

55: Discharge of raffinate to LX

FIG. 3/13

The figure on the left represents the lateral exterior view of a EWSmodule of 4 cells.

The figure in the center corresponds to a lateral interior section of anEWS module of 4 cells.

The figure on the right presents the upper and lower filling circuits ofthe PLS/Electrolyte/Raffinate/ILS.

1: Intercell bar

2: Intercell guide bar

3: Capping board

4: Primary collector with multiple unitary outlets for each module

5: Secondary collector with single outlet of the harvesting of theprimary collector

6. Cathode

7. Transversal bar of the cathode

8. Transversal bar of the anode

9. Structural arm of the anode

10. Exterior wall of the module

11. Holes for filling the PLS/Electrolyte/Raffinate/ILS, connectionpiping ³/₄ NPT

16. Anodic/cathodic supports

17. Discharge of individual solution by overflow

FIG. 4/13

The image on the upper left corresponds to a lateral interiorrepresentation of the module, in the center and right one can see frontand rear exterior lateral views of the module respectively.

The lower left image represents the same module with 10 cells in a rearinterior lateral view.

The inferior image of the center represents a module in volume with 10cells in a rear exterior view at an angle that permits viewing thedischarge by overflowing of the PLS/Electrolyte/Raffinate/ILS.

The image on the lower right represents a module in volume with 10 cellsin an isometric exterior view at an angle that permits seeing the entryand exit by overflow of the PLS/Electrolyte/Raffinate/ILS, including thePL S/Electrolyte/Raffinate/ILS entry pipes.

1. Intercell bar

2. Intercell guide bar

6. Cathode

9. Structural arm of the anode

10. Exterior wall of the module

11. Holes for the filling of the PLS/Electrolyte/Raffinate/ILS,connection piping ³/₄ NPT

13. Anode

14. Internal wall of the module

15. Cell

17. Exit of individual solution by overflow.

FIG. 5/13

The figure on the upper left represents a stripped conceptual volumetricimage of the module, the image on the upper right corresponds to anupper lateral-frontal volumetric integral image with a section of themodule with cathodes and anodes, and finally, the lower image presentsan upper lateral-frontal volumetric integral detailed image of themodule without cathodes and anodes. (For greater clarity, all the imagesdo not show the entry pipes of PLS/Electrolyte/Raffinate/ILS.

1. Intercell bar

2. Intercell guide bar

3. Capping board

4. Primary collector with multiple unitary outlets for each module

5. Secondary collector with single outlet of the gathering of theprimary collector.

6. Cathode

11. Holes for filling of the PLS/Electrolyte/Raffinate/ILS, connectionpiping 3/4 NPT

12. External lateral wall of the module (this wall is narrower than thefrontal wall)

13. Anode

14. Internal wall of the module

15. Cell

16. Anodic/cathodic supports

17. Exit of individual solution by overflow

FIG. 6/13

The figures on the upper left present a view from above of the modulewhere the position of the cathodes and anodes of 4 cells (upper figure)can be seen and where the module is seen empty for 4 cells (inferiorfigure).

The upper figure on the right presents a view from above of the 10-cellmodule without cathodes and anodes.

The figure on the lower left presents a volumetric view from above ofthe 10-cell module without cathodes and anodes.

The figure on the upper right presents an upper schematic view of the10-cell module with the entry pipes of the PLS/Electrolyte/Raffinate/ILSand with the exit cavities for the same.

1. Intercell bar

2. Intercell guide bar

3. Capping board

10. Exterior wall of the module

11. Holes for filling of the PLE/Electrolyte/Raffinate/ILS andconnection piping 3/4 NPT.

14. Internal wall of the module

14. Cell

16. Anodic/cathodic supports

17. Exit of individual solution by overflow

FIG. 7/13

This figure shows, on the left, an isometric view in volume of thelayout of the cathodes and anodes in the EWS module. On the other hand,positioned on the right in the upper center there is a zoom on theconnections between the electrodes and the Capping board, with atriangular type intercell bar, the figure of the lower center shows thesame configuration but with a circular type intercell bar, in the upperright the above-mentioned diagram presents an upper view of the cappingboard, under this, also to the right of the total diagram, there are twolateral views of the capping board, the upper image presents atriangular type intercell bar and the inferior image a circular typeintercell bar.

1. Intercell bar

2. Intercell guide bar

3. Capping board

18. Intermodule connector (this piece permits connecting the continuouscurrent switches, connecting or disconnecting each module electrically).

FIG. 8/13

The figure on the right clearly presents the devices in volume of theexit of the PLS/Electrolyte/Raffinate/ILS from the EWS module.

The figure on the left presents the separation that must exist betweenthe collectors that permits an adequate isolation, avoiding leaks of thecurrent of the electrowinning process (the outlet tubes of the firstcollector are not in contact with any piece of the second collector.

4. Primary collector with multiple unitary outlets for each module.

5. Secondary collector with only outlet of the harvesting of the primarycollector

17. Exit of individual solution by overflow

19. Only exit of PLS/Electrolyte/Raffinate/ILS of the secondarycollector.

FIG. 9/13

The upper figure represents an extended structural descriptive diagramof the EWS module (possesses more than 4 modules), where one can clearlysee how the electric field in series runs maintaining an even loadvolume in all the cells, EWS modules and in the general EW bay.

On the other hand, one can see how the PLS in high volume travels inindependent and parallel form in each cell inside the module.

N: represents the entry of PLS to the cell.

O: represents a cell that is made up of an anode and cathode that formits walls, the entry and exit of the flow of PLS and the electricalconnections necessary to energize the module.

P: represent the exit of PLS from the cell.

a: anode

c: cathode

The lower figure represents a descriptive electric diagram of the EWSmodule with three operative modules, where the movement of the electricfield in series is presented clearly and one can clearly see how thefirst electrode of the module is only an anode and the last electrode ofthe module is only a cathode. Also reflected is the management of theflow rates of PLS/Electrolyte/Raffinate/ILS in a parallel manner in eachindependent module.

FIG. 10/13

The upper figure represents the traditional diagram (state of the art)of an electroplating cell where the electrical fields run in paralleland the flow rates of PLS/Electrolyte/Raffinate/ILS previously extractedby solvents, are not handled in an independent and isolated manner, theflow rates are communicated between anodes and cathodes and in theentire cell.

The lower figure represents a descriptive electric diagram of atraditional cell where the movement of the electric field in parallel ispresented clearly. Also reflected is the managing of the flow rates ofelectrolyte in series in the entire cell.

FIG. 11/13

This figure presents the diagram of the electric circuits with which anEWS module of four EW cells is fed. Operatively, at least two cells arecontrolled by an independent rectifier. The diagram only shows one cellbut, in reality, they control 20 more; it all depends on the design ofthe plant.

20. Represents the circuit of a rectifier transformer with a nominalcurrent of 500A and voltage of 10V DC. In the case of a larger number ofmodules (10) maintaining a larger number of cells (10), the total cellswould be 100 and their control through a transformer with nominalcurrent of 500A and voltage of 220V.

21. Electrical diagram of continuous current switch.

22. EWS module

23. Cells of the EWS module

24. Connection (evacuation of the cells—piping—valves) that permitsremoving the crud from the cells to clean them or to empty thePLS/Electrolyte/Raffinate/ILS or another related solution.

FIG. 12/13

This figure presents three lateral diagrams, in an upper and frontalangle of the interconnection between EWS modules.

18. Intermodule connector

25. Continuous current switch

26. Cable from the rectifier

27. Cable toward the switch

FIG. 13/13

This figure presents three photographs of a prototype to scale 15% ofthe real EWS module, although the EWS module may have other largerdimensions with cathodes 3/4 among others than the industry and thedesign required. The photograph on the upper left shows the laboratoryprototype connected volumetrically with the PLS/Electrolyte,Raffinate/ILS moving in parallel through each cell. The photograph onthe upper right shows the EWS module operating volumetrically andelectrically and as you can see, the electrical connections to therectifier only take place in the electrodes at the ends for the EWSmodules because internally the cells are and operate connected inseries.

4. Primary collector with multiple unitary outlets for each module.

6. Cathode

11. Holes for the filling of the PLS/Electrolyte/Raffinate/ILS andconnection piping ³/₄ NPT

17. Exit of individual solution by overflow

26. Cable from the rectifier

DETAILED DESCRIPTION OF THE INVENTION

The productive process of obtaining cathodes of different metals, suchas Al, Cu, Zn, Au, among other metals with the same characteristics,preferably copper, begins based on the irrigation of ore pads, where thematerial is processed previously through an agglomeration stage andsubsequently is transported and heaped in an additional pad for thispurpose, in the lixiviation (LX) area.

These pads are watered with a raffinate solution that comes from thespent solutions of the cells and then with a recirculated solution ofILS that is formed based on the lixiviation solutions with a lowconcentration of copper, process water and in addition to the adding ofsulfuric acid that the process requires for its progressive enrichmentin copper, which is then sent to the electrowinning (EW) area in PLScategory.

In this area, the PLS solution is conditioned on line, with the additionand replenishment of the anodic and cathodic additives (cobalt sulfateand guar), reagents (sulfuric acid) and processing water. Prior toentering the electrowinning (EW), the solution is conditioned thermallyso that the process is carried out under optimum operating conditions.

On the other hand, volumetrically, once the electrowinning process hasbeen overcome through the EWS (Electrowinning Series) modules, thesolution is transported towards a disposal tank (disposal TK), whichonce again sends the solution towards the initial discharge pool in LX.

The latter is carried out a specific number of times until the copperconcentration in the solution is lowered to an established value. Oncethis objective is achieved, the electrolytic solution, when it leavesthe EW bay for the umpteenth time, is derived to the LX area towards thesame pool section, but as a raffinate, for re-enrichment in copper andreturns to the electrolytic process, thus handling continuous volumes ofelectrolytic solution.

In the meantime, parallel to this operation, the PLS solution producedin LX is sent simultaneously towards the EWS line in place of theprevious one, thus completing the fundamental operation and processingof solutions in the plant between both stages.

The EW-LED process is applied to the EWS device module formed by manycells in this invention, from which cathodic copper in the form ofsheets measuring 1×1 meter or 1 m² and weighing 42 kg are obtained asthe final product, where the cathode assembly plus the copper extractedweighs about 100 kg, with a purity equal to or higher than 98% of Cu,which is stored, packed and dispatched for its commercialization (FIGS.1 and 2, L1, L2).

Device of the EWS Module

The fresh PLS generated in the lixiviation (LX) stage is sent via pipingto the mobile EW-LED plant, in a minimum flow range of 3 liters perminute per square meter of cathode to a maximum of 25 liters per minuteper square meter of cathode. Culminating these steps, the PLS isconditioned with cobalt sulfate and guar, and is finally sent towardsthe EWS modules for the Electrowinning Series (EWS), as can be seen inFIG. 9.

The EWS module device for electrowinning copper (EWS Module) is made upof an assembly of electrolytic cells contained within this cell-shapedmodule connected in series. Each EWS module has a number of cells (2 to10) and these, in turn, are each formed by an anode-cathode pair (FIG.9). Each cell contains a cathode with an operative area of 1 m², fromwhich a copper product is obtained having the same area mentioned, andfrom the anode a minimum current density range is imposed of 150 A/m²and a maximum of 1000 A/m², preferably 300 A/m², which is circulated andcontrolled in series by each cell and EWS module consecutively. Thisoperation format with modules in series (made up of different EWSmodules), opens the possibility of working with different currentdensities in each one of them, considering a minimum current density ofpreferably between 150 to 170 A/m², depending on the chemical quality ofthe PLS to be processed (FIG. 11/13). If the plant works at one samecurrent, it must operate at a nominal current density of 250 A/m², toachieve the normal production planned.

In the case of processing electrolytes with a high concentration ofcopper, the density of the current could reach 1000 A/m².

The EWS module itself is a tank with internal separations that definethe cathode-anode cells. These separations are airtight, which meansthat each volume of PLS passes independently through each cell, withoutconnecting volumetrically or electrically with the parallel cells. Onthe other hand, the electrical connection between cells takes placethrough an intercell bar (1), which has round, triangular and roundlateral forms, preferably a round form where the intercell bar is adiscontinuous bar made up of short bars, or pieces that join thecathodes and anodes of the adjacent cells that cover the entire module.These intercell bars are short, so that they can operate independentlyin each cell, avoiding electrical contact in one same cell. In otherwords, in the places where the bar is complete, it contacts the anodeand cathode of adjacent cells, thus each cell behaves electrochemicallyin an independent manner and electrically in connection in series withthe other cells. These intercell bars (1) are placed in an intercell barguide (2) which is placed over the capping board (3) to correctly placethe bars, cathodes and anodes for a good independent electrical contactper cell. (FIG. 5).

Structurally, the module within the watertight intercell internalseparations, has depressions or supports that make fast the cathodes andanodes. These cathodic/anodic depressions or supports (16) leave onlyone face of the anodes and cathodes exposed because the other face isplaced on the watertight intercell dividing wall. This means that theharvesting process of the cathodes is only carried out on one side ofthe electrode (FIGS. 4 and 6).

The anodic/cathodic supports also permit regulating the separationbetween the anode and cathode, in the range of 10 to 100 mm, preferablyfrom 15 and 70 mm. This characteristic means that the distance betweenthe centers of anodes and cathodes can be regulated depending on therequirements of the productive process and its efficiency.

The modules and cells operate in the following manner, which includesthe stages of:

-   -   a) Filling of the EWS module with PLS/Electrolyte/Raffinate/ILS        between 30° C. to 50° C. through the volumetrically independent        cells via the piping and upper and lower inlets until the level        of the PLS/Electrolyte/Raffinate/ILS reaches the overflow zone        and overflows. This filling is controlled manually or        automatically through valves placed in the inlet pipes;    -   b) Circulation of current from the anode in a minimum current        density range of 150 A/m² and maximum of 1000 A/m², preferably        300 A/m² which is circulated and controlled in series by each        cell and EWS module consecutively, considering a minimum current        of preferably between 150 to 170 A/m², depending on the chemical        quality of the PLS/Electrolyte/Raffinate/ILS to be processed;    -   c) The EWS modules operate through cycles where the        PLS/Electrolyte/Raffinate/ILS passes between 3 and 15 times,        preferably 6 times, until the concentration of Cu²+ is at the        lowest metallurgical minimum possible of about 4 to 5 g/L, which        will depend on the physical conditions of the        PLS/Electrolyte/Raffinate/ILS being processed;    -   d) Reaching the selected weight of the metal cathode, preferably        copper, preferably between 36 and 56 kg and harvesting of the        anodes.

To achieve planned production, the assembly of EWS modules works at onesame current, with a nominal current density of 300 A/m².

The connection and disconnection process of the different modules,according to FIG. 12, consists of:

After the copper cathodes reach a weight predetermined by the operator,preferably in the range of 36 and 56 kg, specifically 42 kg, the controlsystem (PLC) that keeps control of the current applied to the cathodes(directly by Faraday's Law) uses a signal to activate the opening of thecontinuous current switches that permit the disconnection of the EWSmodule and thus of its cells (bridging of the EWS modules) that permitharvesting the cathodes of the cells;

In parallel, the flow of PLS/Electrolyte/Raffinate/ILS continuescirculating freely through the cells of the EWS Module that is beingharvested; this means that when the cells are loaded with new cathodes,the concentration of copper will be uniform and the temperature of thesolution will be uniform;

Electrical physical disconnection of modules arranged together(consecutive) through the separation of the inter-module connectors(18), following upon the bridging of the circuit through a continuouscurrent switch;

Lifting the cathode assembly and harvesting the metal, preferablycopper, through a cathode holder connected to the hoist;

Replacement of previously prepared cathodes in the cells of the EWSmodule;

Connection of new module via intermodule continuous current switches(18), thus eliminating the electric bridge formed by the continuouscurrent switches leaving the continuous electrical connection of allexisting modules plus the new integrated module, without requiring thedetaining of the complete process, only the module to be harvested.

Volumetrically, the PLS/Electrolyte/Raffinate/ILS that enters the EWSmodule, penetrates through the upper part of each module (11) throughthe feed piping of each cell (each cell also has a lower electrolyteinput and an independent outlet through each cell) and it spills over(17) as is shown in FIGS. 3 and 4.

After the PLS/Electrolyte/Raffinate/ILS overflows it is capturedindependently by each cell via an outlet (17) that falls into a primarycollector (4) that independently releases the flow ofPLS/Electrolyte/Raffinate/ILS to a secondary collector (5) separatedphysically from the primary collector to avoid electrical losses (aspresented in FIG. 8). The secondary collector releases thePLS/Electrolyte/Raffinate/ILS to the next accumulation tank (K5, K6, K7and K8 of FIGS. 1 and 2).

The material used to manufacture the EWS modules is anticorrosivematerial, such as polymeric concrete structures coated in fiberglass, ingeneral, materials that are resistant to PLS/Electrolyte/Raffinate/ILS.On the other hand, a specific example of its dimensions is1.300×1.250×1.600 mm (length, width and height respectively), withoutrestricting other measurements required in view of its application.

The material used to manufacture the electrodes will depend on thequality of the water to be used in the plant. If water with a highcontent of active chlorine is used, such as seawater, both electrodeswill be titanium-based, and in the case of water being used that islight in chlorides or chloride-free, such as potable water ordemineralized water, conventional electrodes will be used: stainlesssteel 316L as cathodes and lead-calcium-tin alloy in the anodes.

The PLS/Electrolyte/Raffinate/ILS in circulation in the EW bay isconducted from module to module by a drive system through feed tankspreviously situated individually in each module, adding, at the sametime, a replacement solution of Guar.

Once the outgoing solution has been treated in the modules, it is sentto a transfer tank (Transfer TK) and driven towards the E/E heatexchanger up to the PLS sub-pool in recirculation batch, thus fulfillinga cycle of PLS passage in the plant (as can be seen in FIGS. 1 and 2,J4).

This operation of cycles (sending and returning of PLS in process fromLX) is carried out between 3 and 15 times, preferably 6 times, until theconcentration of Cu²+ is lowered to the minimum metallurgically possible(around 4 to 5 g/L), which will depend on the physical conditions of theelectrolyte being processed, which in turn will depend on thecharacteristics of the ore processed and also on the operation beingexecuted.

The final product of the EW-LED process is cathodic copper in sheets ofapproximately 42 kg, with an area of 1 m² and a purity equal or higherthan 98%; which is washed, detached from the cathode, rolled and storedin the dispatch patio for its commercialization (FIGS. 1 and 2, F7).

To summarize, the LED module is used in a new hydrometallurgical processthat presents four big innovations, with respect of the conventionalprocess, that are the following:

Permits electrowinning copper cathodes, where the continuous current ofthe electric power system is exactly the same as the current theelectrochemical process requires for electrowinning the cathodes,permitting a direct control over Faraday's law to determine the weightof the cathodes that will be harvested. That is, the electrowinningprocess is a circuit of continuous current in series (FIG. 9), while theconventional technology is in parallel (FIG. 10).

The electrowinning of copper in the cells can be carried out fromsolutions of: PLS, ILS, Raffinate, Pregnant Electrolyte or discardelectrolyte of the electrowinning, differing from the conventionalprocess that requires the extraction by solvents stage to obtainpregnant electrolyte that is the only solution it accepts to feed thecells for electrowinning high quality cathodes.

The flow of PLS that feeds the electrowinning cells is over 5 times theflow of electrolyte that conventional plants require.

The electrowinning can be carried out from low concentrations of PLSthat go from 5 to 50 g/L, obtaining cathodes with a high concentrationof copper (from 97%).

The low temperature (30° C. to 50° C.) that the conditioning of the PLSrequires when entering the electrowinning module, results in a lowergeneration of corrosive gases from the modules and their need to beextracted, and also reduces the consumption of electricity.

Operation of the EWS Module

The flow of PLS required in this process feeds, in parallel and inseries, the different EWS modules of the electrowinning cells which mustcontain between 4 to 50 grams of copper per liter of solution, at themoment of starting the process, reagents such as guar gum and cobaltsulfate are incorporated into the solution, with a dosage of about 320grams and 220 ppm per ton of copper produced respectively, as additivesfor the cathodes and the anodes respectively prior to entering the cellsof the EWS modules.

The PLS is recirculated with a flow in parallel-series configuration inthe system until it is resent to the lixiviation heaps when it isbetween 4 and 6 grams of copper per liter of solution.

Another relevant aspect for the optimum functioning of the EW-LEDprocess is the temperature of the PLS that feeds the EWS modules andthus the cells, which must oscillate between 30 and 50° C.

On the other hand, each electrowinning EWS module, EW-LED, consists ofbetween 2 to 20 cells, with a preferred configuration in the EW bay thatconsists of 60 operative cells, volumetrically independent and compact,with each one of the cells formed by a cathode and an anode; thedistribution of the electrical connections in the cells are connected inseries between cathodes and anodes and integrated, with the purpose ofmaintaining an identical continuous current and the same current densityin the entire module and intermodules; the operative area of the cathodelies within the range of 0.3 m² to 2 m² preferably 1 m²; the density ofthe current is regulated in the module in a range between 0 and 500amperes, with an operative current density between 150 and 500 amperesper m² of cathode; there is also a channeling with independent controlof the flow of PLS/Electrolyte/Raffinate/ILS per cell and module; and anindependent electric field for each one of the cells through theelectricity fed by rectifier transformers (FIG. 11).

A specific example of this invention is the EW bay where the EWS processis produced. This EW bay is made up of a series of modules, between 1 to10 EWS modules, preferably 6, and each module contains between 1 and 20cells, preferably 10. Therefore, a preferred configuration would have atotal of 60 cathodes in the EW bay.

One of the important parts of the module is channeling, with independentcontrol of the flow of PLS/Electrolyte/Raffinate/ILS that permitsfeeding with a variable flow, between 3 and 30 L/min/m² of cathode, to agroup of modules and independently to each electrowinning cell.

There is a direct relationship between the control of the flow ofPLS/Electrolyte/Raffinate/ILS, that depends on the concentration ofcopper in the solution and the number of operative cells that are usedin the electrowinning of copper. This relationship states that thesmaller the concentration of copper in the solution the greater the flowand permits controlling the continuous current in the electrowinningprocess.

DESCRIPTION OF THE FIGURES

FIG. 1

The figure represents a general diagram of the productive process inwhich this invention is inserted.

The line of arrows of the upper part of the diagram shows the physicalphenomena that the water suffers in the different positions of themovement of the ore:

X: Impulse pumps

O: Flow controllers and temperature meters

F1: Evaporation of the mixed pool

F2: Evaporation of the ILS pool

F3: Evaporation piles

F4: Evaporation in EW

F5: Decomposition of water by electrolysis

F6: Washing water to discard

F7: Production of copper cathode

The line immediately below the arrows of the upper part shows thebehavior of the solid material in the different positions of themovement of the ore:

G1: Agglomerated ore from the crusher-binder

G2: Dynamic pile

G3: Gravel to dump

In the following line of arrows, the handling of the acid is presented:

H1: Sulfuric acid from trucks

H2: Acid TK

H3: Sulfuric acid to agglomeration.

In the following line of arrows, the handling of the process water ispresented:

I1: Process water from water supply

I2: Service water

I3: ILS pool

I4: Mixed pool

I5: Emergency pool

The last line presents the system's heating network:

J1: Oil supply

J2: Boiler

J3: Water conditioning chamber

J4: Heat exchangers

There are other parts associated to the adaptation and preparation ofthe LPS before the EW-LED:

K1: Chemical product, concentrated Guar

K2: Chemical product, concentrated cobalt sulfate

K3: Guar TK, this is a tank where the Guar is diluted in water and isleft at an optimum concentration to be applied to the PLS that is sentto the cells of the modules of the EW-LED plant.

K4: Cobalt TK, this is a tank where the cobalt sulfate is diluted inwater and is left at an optimum concentration to be applied to the PLSthat is sent to the cells of the EWS modules of the EW-LED plant.

K5: TK Bank 2, this is a tank where the PLS/Electrolyte/Raffinate/ILS isreceived, in series, when it has passed once through the first bank ofthe EW-LED system. (Without restricting the number of banks to be usedexcept when the concentration of the PLS/Electrolyte/Raffinate/ILSreaches a range below 4 g/L.)

K6: TK Bank 3, this is a tank where the PLS/Electrolyte/Raffinate/ILS isreceived in series when it has passed once through the second bank ofthe EW-LED system. (Without restricting the number of banks to be usedexcept when the concentration of PLS/Electrolyte/Raffinate/ILS reaches arange below 4 g/L.)

K7: TK Bank 4, this is a tank where the PLS/Electrolyte/Raffinate/ILS isreceived, in series, when it has passed once through the third bank ofthe EW-LED system. (Without restricting the number of banks to be usedexcept when the concentration of copper in the PLS solution reaches arange below 4 g/L.)

K8: TK transfer bank, this is a tank where the PLS is received, inseries, that has passed once through the fourth bank of the EW-LEDsystem. (Without restricting the number of banks to be used except whenthe concentration of the PLS reaches a range below 4 g/L.) The PLS usedis transferred to the mixed pool.

L1: EW-LED bank No 1 (this invention)

L2: EW-LED bank No 2 (this invention)

L3: EW-LED bank No 3 (this invention)

L4: EW-LED bank No 4 (this invention)

FIG. 2

This figure represents a flow diagram of the Electrowinning processdirect in series EW-LED.

In the line of arrows of the lower right part of the diagram, thephysical phenomena that the water suffers in the different positions ofthe movement of the ore are presented:

F5: Decomposition of water by electrolysis

F6: Washing water to discard

F7: Production of copper cathodes

F8: Evaporation of water by atmosphere

F9: Cathode washing water

The following line of arrows presents the handling of the acid:

X: Impulse pumps

O: Flow controllers and temperature meters

H4: Sulfuric Acid to EW-LED.

The following line of arrows presents the handling of the process water:

16: Process water to EW-LED

17: LX emergency shower

18: Service water for human consumption

The last line presents the system's heating network:

J1: Oil supply

J2: Boiler

J3: Water conditioning chamber

J4: Heat exchangers

There are other parts associated to the adaptation and preparation ofthe PLS before the EW-LED:

K1: Chemical product, concentrated Guar

K2: Chemical product, concentrated cobalt sulfate

K3: Guar TK, this is a tank where the Guar is diluted in water and isleft at an optimum concentration to be applied to the PLS that is sentto the cells.

K4: Cobalt TK, this is a tank where the cobalt sulfate is diluted inwater and is left at an optimum concentration to be applied to the PLSthat is sent to the cells.

K5: TK Bank 2, this is a tank where the PLS is received, in series, whenit has passed once through the first bank of the EW-LED system. (Withoutrestricting the number of banks to be used except when the concentrationof the PLS reaches a range below 4 g/L.)

K6: TK Bank 3, this is a tank where the PLS is received, in series, whenit has passed once through the second bank of the EW-LED system.(Without restricting the number of banks to be used except when theconcentration of the PLS reaches a range below 4 g/L.)

K7: TK Bank 4, this is a tank where the electrolyte in series isreceived when it has passed once through the third bank of the EW-LEDsystem. (Without restricting the number of banks to be used except whenthe concentration of copper in the PLS solution reaches a range below 4g/L.)

K8: TK transfer bank, this is a tank where the PLS is received, inseries, that has passed once through the fourth bank of the EW-LEDsystem. (Without restricting the number of banks to be used except whenthe concentration of the PLS reaches a range below 4 g/L.)

The PLS used is transferred to the mixed pool.

L1: EW-LED bank No 1

L2: EW-LED bank No 2

L3: EW-LED bank No 3

L4: EW-LED bank No 4

The following line of arrows presents the handling of the PLS and aline:

M3: PLS/PLS recirculated from LX

M4: PLS recirculated/raffinate to LX

The following numbering also shows:

21: PLS to conditioning

22: Sulfuric acid to line

23: Process water to line

24: PLS to E/E heat exchanger

25: PLS to E/A heat exchanger

26: Cobalt sulfate to Cobalt Sulfate TK

27: Guar to Guar TK

28: Cobalt sulfate solution

29: Guar solution to distribution

30: Guar solution to Bank EW 1

31: Guar solution to Bank EW 2

32: Guar solution to Bank EW 3

33: Guar solution to Bank EW 4

34: PLS to Bank EW 1

35: PLS to Bank EW 2

36: PLS to Bank EW 3

37: PLS to Bank EW 4

38: PLS to Transfer TK

39: PLS in recirculation to pool

40: Hot water from heater

41: Hot water to Cobalt Sulfate TK

42: Hot water to Guar TK

43: Hot water to heat exchanger

44: Hot water to cathode washing

45: Hot water in return

46. Process water to services and operation

47. Water to EW-LED emergency service

48. Service water to human consumption

49. Process water to replacement

50: Water to heater

51: Petroleum to heater

52: Evaporation of water in EW bay

53: Decomposition of water in EW bay

54. Cathodic copper

55: Discharge of raffinate to LX

FIG. 3

The Figure represents the lateral exterior view of a EWS module of 4cells, a lateral interior section of an EWS module of 4 cells, and theupper and lower filling circuits of the PLS/Electrolyte/Raffinate/ILS).

1: Intercell bar

2: Intercell guide bar

3: Capping board

4: Primary collector with multiple unitary outlets for each module

5: Secondary collector with single outlet of the harvesting of theprimary collector

6. Cathode

7. Transversal bar of the cathode

8. Transversal bar of the anode

9. Structural arm of the anode

10. Exterior wall of the module

11. Holes for filling the PLS/Electrolyte/Raffinate/ILS, connectionpiping ¾ NPT

16. Anodic/cathodic supports

17. Discharge of individual solution by overflow

FIG. 4

The images correspond to a lateral interior representation of themodule, front and rear exterior lateral views of the module, the modulewith 10 cells in a rear interior lateral view, a module in volume with10 cells in a rear exterior view at an angle that permits viewing thedischarge by overflowing of the PLS/Electrolyte/Raffinate/ILS, and amodule in volume with 10 cells in an isometric exterior view at an anglethat permits seeing the entry and exit by overflow of thePLS/Electrolyte/Raffinate/ILS, including thePLS/Electrolyte/Raffinate/ILS entry pipes.

1. Intercell bar

2. Intercell guide bar

6. Cathode

9. Structural arm of the anode

10. Exterior wall of the module

11. Holes for the filling of the PLS/Electrolyte/Raffinate/ILS,connection piping ¾ NPT

13. Anode

14. Internal wall of the module

15. Cell

17. Exit of individual solution by overflow.

FIG. 5

The figure represents a stripped conceptual volumetric image of themodule, an upper lateral-frontal volumetric integral image with asection of the module with cathodes and anodes, and finally, an upperlateral-frontal volumetric integral detailed image of the module withoutcathodes and anodes. (For greater clarity, all the images do not showthe entry pipes of PLS/Electrolyte/Raffinate/ILS).

1. Intercell bar

2. Intercell guide bar

3. Capping board

4. Primary collector with multiple unitary outlets for each module

5. Secondary collector with single outlet of the gathering of theprimary collector.

6. Cathode

11. Holes for filling of the PLS/Electrolyte/Raffinate/ILS, connectionpiping ¾ NPT

12. External lateral wall of the module (this wall is narrower than thefrontal wall)

13. Anode

14. Internal wall of the module

15. Cell

16. Anodic/cathodic supports

17. Exit of individual solution by overflow

FIG. 6

The figure presents a view from above of the module where the positionof the cathodes and anodes of 4 cells can be seen and where the moduleis seen empty for 4 cells, a view from above of the 10-cell modulewithout cathodes and anodes, a volumetric view from above of the 10-cellmodule without cathodes and anodes, and an upper schematic view of the10-cell module with the entry pipes of the PLS/Electrolyte/Raffinate/ILSand with the exit cavities for the same.

1. Intercell bar

2. Intercell guide bar

3. Capping board

10. Exterior wall of the module

11. Holes for filling of the PLE/Electrolyte/Raffinate/ILS andconnection piping ¾ NPT.

14. Internal wall of the module

14. Cell

16. Anodic/cathodic supports

17. Exit of individual solution by overflow

FIG. 7

This figure shows, an isometric view in volume of the layout of thecathodes and anodes in the EWS module, a zoom on the connections betweenthe electrodes and the Capping board, with a triangular type intercellbar, the same configuration but with a circular type intercell bar, anupper view of the capping board, two lateral views of the capping board,a triangular type intercell bar, and a circular type intercell bar.

1. Intercell bar

2. Intercell guide bar

3. Capping board

18. Intermodule connector (this piece permits connecting the continuouscurrent switches, connecting or disconnecting each module electrically).

FIG. 8

The figure presents the devices in volume of the exit of thePLS/Electrolyte/Raffinate/ILS from the EWS module, and the separationthat must exist between the collectors that permits an adequateisolation, avoiding leaks of the current of the electrowinning process(the outlet tubes of the first collector are not in contact with anypiece of the second collector).

4. Primary collector with multiple unitary outlets for each module.

5. Secondary collector with only outlet of the harvesting of the primarycollector

17. Exit of individual solution by overflow

19. Only exit of PLS/Electrolyte/Raffinate/ILS of the secondarycollector.

FIG. 9

The upper figure represents an extended structural descriptive diagramof the EWS module (possesses more than 4 modules), where one can clearlysee how the electric field in series runs maintaining an even loadvolume in all the cells, EWS modules and in the general EW bay.

On the other hand, one can see how the PLS in high volume travels inindependent and parallel form in each cell inside the module.

N: represents the entry of PLS to the cell.

O: represents a cell that is made up of an anode and cathode that formits walls, the entry and exit of the flow of PLS and the electricalconnections necessary to energize the module.

P: represents the exit of PLS from the cell.

a: anode

c: cathode

The lower figure represents a descriptive electric diagram of the EWSmodule with three operative modules, where the movement of the electricfield in series is presented clearly and one can clearly see how thefirst electrode of the module is only an anode and the last electrode ofthe module is only a cathode. Also reflected is the management of theflow rates of PLS/Electrolyte/Raffinate/ILS in a parallel manner in eachindependent module.

FIG. 10

The upper figure represents the traditional diagram (state of the art)of an electroplating cell where the electrical fields run in paralleland the flow rates of PLS/Electrolyte/Raffinate/ILS previously extractedby solvents, are not handled in an independent and isolated manner, theflow rates are communicated between anodes and cathodes and in theentire cell.

The lower figure represents a descriptive electric diagram of atraditional cell where the movement of the electric field in parallel ispresented clearly. Also reflected is the managing of the flow rates ofelectrolyte in series in the entire cell.

FIG. 11

This figure presents the diagram of the electric circuits with which anEWS module of four EW cells is fed. Operatively, at least two cells arecontrolled by an independent rectifier. The diagram only shows one cellbut, in reality, they control 20 more; it all depends on the design ofthe plant.

20. Represents the circuit of a rectifier transformer with a nominalcurrent of 500 A and voltage of 10V DC. In the case of a larger numberof modules (10) maintaining a larger number of cells (10), the totalcells would be 100 and their control through a transformer with nominalcurrent of 500 A and voltage of 220V.

21. Electrical diagram of continuous current switch.

22. EWS module

23. Cells of the EWS module

24. Connection (evacuation of the cells-piping-valves) that permitsremoving the crud from the cells to clean them or to empty thePLS/Electrolyte/Raffinate/ILS or another related solution.

FIG. 12

This figure presents three lateral diagrams, in an upper and frontalangle of the interconnection between EWS modules.

18. Intermodule connector

25. Continuous current switch

26. Cable from the rectifier

27. Cable toward the switch

FIG. 13

This figure presents three photographs of a prototype to scale 15% ofthe real EWS module, although the EWS module may have other largerdimensions with cathodes 1 m², 1.1 m², 1.2 m² among others than theindustry and the design required. The photograph on the upper left showsthe laboratory prototype connected volumetrically with thePLS/Electrolyte, Raffinate/ILS moving in parallel through each cell. Thephotograph on the upper right shows the EWS module operatingvolumetrically and electrically and as you can see, the electricalconnections to the rectifier only take place in the electrodes at theends for the EWS modules because internally the cells are and operateconnected in series.

4. Primary collector with multiple unitary outlets for each module.

6. Cathode

11. Holes for the filling of the PLS/Electrolyte/Raffinate/ILS andconnection piping ¾ NPT

17. Exit of individual solution by overflow

26. Cable from the rectifier

EXAMPLES OF APPLICATION

This application example presented in FIG. 13 shows a laboratory deviceat a scale at 15% (FIG. 13) of what would be the real prototypedimensioned at 1 m² of cathode, without restricting that the dimensionof the cathodes is given mainly by the model that the customer finallyneeds. Other measurements of 1.1 m² or 1.2 m² can also exist.

The concentrations of copper handled for this equipment were about 14 to15 g/1 of PLS per pass in the electrolytic cells with flow rates from2.5 to 3.0 l/min/m² of cathode. With a current density of 1.73 A/m²after 24 to 34 hours, copper cathodes between 40 and 70 grams wereobtained, 99.99% purity, with a current efficiency between 95% and 99%.

The invention claimed is:
 1. An EWS module device for electrowinningand/or electrorefining, based on a pregnant leach solution (PLS) withoutextraction by solvents, comprising: a tank; a group of electrolyticcells contained within the tank, where the cells are separatedelectrically and volumetrically by internal walls of the EWS moduledevice and the cells are connected in series by a capping board; anintercell bar; an intercell guide bar; entry and exit ducts for a mixedsolution of PLS/Electrolyte/Raffinate/intermediate leach solution (ILS)and for each cell independently; and an intermodule connector forinterconnecting the EWS module device to another EWS module device,where the intermodule connector regulates the connection anddisconnection of the EWS module device via a continuous current switch,wherein the electrolytic cells include two consecutive internal walls ofthe EWS module device; one anodic/cathodic support that permitsregulation of the separation between anode and cathode from 15 to 70 mm;a single cathode and a single anode, each with an area of 1 m², alwaysleaning on one of the internal walls of the cell; the capping board; theintercell bar; the intercell guide bar; the entry and exit for the mixedsolution of PLS/Electrolyte/Raffinate/ILS and by each cellindependently; and the intermodule connectors at the ends of theintercell bars.
 2. The EWS module device of claim 1, wherein the tank isseparated internally and hermetically through the internal walls of theEWS module device where the number of internal walls is equivalent tothe number of cells that the EWS module device will take and is from 4to
 100. 3. The EWS module device of claim 1, wherein the anodic/cathodicsupport is made in a single piece that positions the single anode andsingle cathode against the one of the internal walls of the cell of theEWS module device such that only one side of the single anode and of thesingle cathode is operative.
 4. The EWS module device of claim 1,wherein the intercell bars have lateral forms, triangular or round, andin length the ends are exposed to be connected via the intermoduleconnectors, also, the intercell bar to be able to operate independentlyin each cell, is a discontinuous bar made up of short bars that connectthe anode of one cell with the cathode of the adjacent cell to permitthe continuity of the electric connection in series, the short barsavoid the contact between an anode and a cathode of one same cell, withthis electrical configuration in series each cell behaves electricallyindependently.
 5. The EWS module device of claim 4, wherein theintercell bars are placed or within an intercell guide bar that ispositioned over the capping board to correctly place the bar, cathodesand anodes for a good independent electrical contact per cell.
 6. TheEWS module device of claim 1, wherein the entry and exit ducts of themixed solution of PLS/Electrolyte/Raffinate/ILS are positioned in eachcell independently, where two entry ducts may be placed in a bottom orin an upper part of the cell in opposed positions and the exit ductreceives the mixed solution of PLS/Electrolyte/Raffinate/ILS when itoverflows in the upper part in the EWS module device, independently foreach cell.
 7. The EWS module device of claim 6, wherein the exit ductschannel the mixed solution of PLS/Electrolyte/Raffinate/ILS to a primarycollector independently by each cell and this primary collector deliversthe mixed solution of PLS/Electrolyte/Raffinate/ILS independently andseparated mechanically to a secondary collector that delivers the mixedsolution of PLS/Electrolyte/Raffinate/ILS of all the cells through asingle duct to an accumulation tank independently.
 8. The EWS moduledevice of claim 2, wherein the tank's dimensions are 1.300×1.250×1.600mm (length, width and height, respectively) and the tank is made up ofan anticorrosive material, which includes polymeric concrete, structurescovered with fiberglass, in general, materials resistant toPLS/Electrolyte/Raffinate/ILS at temperatures in the range of 30° C. to70° C.
 9. The EWS module device of claim 1, wherein the material of theelectrodes used as cathodes and anodes will depend on the water to beused in the electrolysis process, where if the water has a high contentof active chlorine both electrodes (cathode and anode) will be titaniumbased, and if water light in or free of chlorides is used, conventionalstainless steel 316 L electrodes will be used as cathodes and the anodeswill be made of a lead-calcium-tin alloy.
 10. An operation process ofthe EWS module device according to claim 1, consisting of the stages of:a) Filling of the EWS module device with the mixed solution ofPLS/Electrolyte/Raffinate/ILS between 30° C. to 50° C. through thevolumetrically independent cells via piping to the entry ducts until thelevel of the mixed solution of PLS/Electrolyte/Raffinate/ILS reaches anoverflow zone and overflows, the filling being controlled manually orautomatically through valves placed in the piping; b) Circulatingcurrent from an anode of each of the cells with a minimum currentdensity of 150 A/m² and a maximum current density of 1000 A/m², which iscirculated and is controlled in series by each cell and by the EWSmodule device consecutively, where the minimum current density isbetween 150 to 170 A/m², depending on the chemical quality of the mixedsolution of PLS/Electrolyte/Raffinate/ILS to be processed; c) Operatingthe EWS module device through cycles where the mixed solution ofPLS/Electrolyte/Raffinate/ILS passes between 3 and 15 times until theconcentration of Cu²+ is lowered to the minimum that is metallurgicallypossible of around 4 to 5 g/L, which will depend on the physicalconditions of the mixed solution of PLS/Electrolyte/Raffinate/ILS beingprocessed; and d) Reaching a selected weight of a copper cathode of eachof the cells between 36 and 56 kg and harvesting the anodes.
 11. Theoperation process of claim 10 wherein stage b) includes assembling aplurality of the EWS module devices working at one same current, with anominal current density of 300 A/m², to achieve a normal plannedproduction.
 12. The operation process of claim 11, further comprisingthe stages of: e) After the copper cathodes reach the selected weight, acontrol system (PLC) that controls current applied to the cathodesactivates by means of a signal the opening of the continuous currentswitches that permit the disconnection of the EWS module device orbridging of the EWS module devices, that permit harvesting the cathodesof the cells; b) In parallel, continue circulating the flow of the mixedsolution of PLS/Electrolyte/Raffinate/ILS freely through the cells ofthe EWS Module device that is being harvested, which permits that whenthe cells are loaded with new cathodes, the copper concentration will beuniform and the temperature of the mixed solution will be uniform; c)Physical electrical disconnection of EWS module devices placed togetherconsecutively through the separation of the intermodule connectors (18)after bridging the circuit via the continuous current switch; d) Raisingthe cathodes and harvesting the copper through a cathode holderconnected to a hoist; e) Replacing previously prepared cathodes in thecells of the EWS module device; f) Connecting a new EWS module devicevia the intermodule continuous current switches (18), therebyeliminating the electric bridge made by the continuous current switches,leaving the continuous electric connection of all the existing EWSmodule devices plus the new EWS module device integrated, withoutneeding to detain the complete process, only that of the EWS moduledevice to be harvested.